Refrigerating apparatus



May 18, 1937. w, w WATT 2,081,025

REFRIGERATING APPARATUS INVENTOR. 0.44/4 W. M77.

m: ATTORNEYS;

May 18, 1937. w, w, wAfi 2,081,025

' REFRIGERATING APPARATUS Filed March 5, 1936 2 Sheets-Sheet 2 INVE R.- WIu/JMJMW r.

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f 6 'ATTOR Patented May 18, 1937 REFRIGERATING arrnm 'ros William W. Watt, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application March 5, 1936, Serial No; 67,409 1 Claim. (Cl. 230-221) This invention relates to compressors of refrigerating systems and particularly to check valves ordinarily incorporated inthe piston or pistons of such compressors.

5 In refrigerating systems embodying a compressor which divides the system into a high pressure portion or side and a low pressure portion or side and which compressor includes a single piston valve, for permitting flow of refrigerant from the compressor crankcase or from the low pressure portion of the refrigerating system into the compressor cylinder to permit compression thereof by the piston, it has been found that an abnormal low pressure is created in the compressor cylinder above the piston upon the initial downward movement of the piston and prior to the opening of the piston valve. The abnormal low pressure in the cylinder causes refrigerant vapor, from the compressor crankcase or from the low pressure portion of the refrigerating system, to suddenly rush into the cylinder above the piston when the piston valve opens with such force that a loud popping noise is created. This noise occurs at each and every downstroke of the piston or pistons during operation of a compressor and is very objectionable. Many diiferent valve constructions have been made in an endeavor to overcome this objectionable noise and to provide a quiet operating compressor. For example, numerous types of single valves have been tried without satisfactory results. Applicants invention is therefore directed to the provision of a double valve arrangement or to two valves in series relation within a compressor piston which successfully eliminates the objectionable noise referred to.

An object of the present invention is to provide f an improved compressor for a refrigerating system.

40 Another object of the present invention is to provide a valve structure or arrangement within the piston of a compressor which will operate efliciently and quietly in order that the compressor in which the valve arrangement is incorporated may be used in refrigerating apparatus of the ho hold type.

A further object of the present invention is to provi e a valve construction or arrangement within th piston ofacompressor of a refrig-.

5U erating systemwhich \will be of long life and quiet in operation.

. In carrying out the iforegoing objects it is a. I

still further and more specific object of the invention to provide two valves one inseries with the other in a piston of a compressor of a refrigerating system in order to eliminate noise inherently present in the operation of compressors having but a single valve within a piston thereof. Further objects and advantages of the present invention will be apparent from the foregoing.

description reference being had to the accompanying drawings, whenein a preferred ,form

of the present invention is clearly shown.

In the drawings:

Fig. 1 is a sectional view of a compressor of a refrigerating system having the present invention embodied therein and showing the refrigerating system. diagrammatically connected to the compressor; I

Fig. 2 is an enlarged vertical sectional view of the piston of the compressor shown in Fig. 1

iii

having my improved valve arrangement incor-.

porated therein;

Fig. I? is a view taken on the line 3-3 of Fig. 2 showing the valve arrangement incorporated in the compressor piston partly in section and partly in elevation; and,

Fig. 4 is a sectional view through the piston taken on line 4-4 of Fig. 2 and showing in plan reference character l0, discharging refrigerant under pressurethrough a conduit 1 i to a condenser II. The compressed refrigerant is cooled conventional manner and flows into a chamber l3 containing a float or otherwise operated valve which controlsthe flow of liquid refrigerant to the evaporator l4. f Refrigerant vaporized in evaporator I4 is drawn through a conduit l5, by suction created bythe compressor ill, back to the compressor preferably to the crankcasethereof.

The evaporator I 4 is adapted to be mounted with-- in an insulated compartment of refrigerator cabinet (not shown) from "which heat is to be extracted. Means for controlling a motor l6 which operates e compressor l0, through suitable belt and pulley connections IT, in response to the temperature produced by the evaporator i4 '40 and liquefied in condenser I! in any suitable or v may be provided. This means may comprise an expansible bellows l8 connected'by a pipe l9 to a bulb 2|, mounted in thermal association with the evaporator l4, and having a volatile fluid sealed thereinfor actuating, upon movement of the bellows l8, 9. switch 22 interposed in the power line leading to motor l8.

Operation of motor l8 drives the compressor shaft 23 through the connections l'l. Rotation of compressor shaft 23 causes rotation of eccentrics' 24 and 25 mounted thereon for operating the pitmen 28 and 21 respectively to cause the compressor pistons 28 to be reciprocated within the cylinders 29. The end of the shaft 23 which extends through a wall of the compressor crank-- case may be sealed by any suitable or convention al sealing means generally indicated at 3|. Outlet check valves, 32 of the type fully disclosed in the Patent No. 1,852,203 to Otto M. Summers on April 5, 1932, mounted within the compressor l8 upon a suitable plate located above the cylinders 29 together with the refrigerant flow control means I 3 divide the refrigeratingsystem into a low pressure portion and a high pressure portion. The low pressure portion of the refrigerating systern includes the evaporator ll conduit l8 and the crankcase or compressor Il 'The valve arrangement in the present disclosure employed to intermittently open and. close the-passage extending through the pistons 28; and which passages establish communication. betweenthe crankcase of compressor l8 and the cylinders 29; comprise the valves 35 and 38 mounted within the pistons 28 one above theIothe -"in series relation with the path of flow of refrigerant the pistons. Referring now toFlgJZit will be noted that the lower valve 35 is in thej'form ofa disk which seats upon the gseat 31 surrouhdizig an opening provided in a 'horlzontalgpart 38, of a cylindrical spider like member 39 mounted-fend secured to the piston'28, The spider like portion ll of member 39 includes a down b y Project ing central stem 42 having a shoulder formed thereon which receives an open walled cage member 43. The cagemember l3 encloses and holds in place the disk valve and spring u (see Fig. 4) which is pted to bearzasain t'valve 3 to 1 or the compressor is thus not materially impaired by my improved double piston check valve normally maintain this valve upon the seat 131, the horizontal part 38 of member 39-may' be welded or staked to member 39 after the c'age'.| 3,

spring 44 and valve 35 have been mounted or located within the cylindrical cup like portion of the member 33 and prior to assembly of the mefii-' ber 39 into the piston 28. The cylindrical spider like member 39 is provided .with a valve seat upon its upper face and after the member 39 is placed in the hollowed out receiving portion therefor provided in the piston 28 the upper piston valve 38 is adapted to be located upon this seat 58. A plate I! having perforations therein providing guiding edges 88- (see Fig. 3) for valve 38 is-placed upon the member 39; The plate 41 has a relatively thin plate 8|, perforated as at 52.

welded, staked or otherwise secured thereto prior to assembly of plate ".upon the piston 28. The thin perforated plate 9| has a spring 53 secured to its in any suitablenor desirable mm Spring 33 may have its one end 84 (see Fig. 3) located in a slot (not shown) provided or cut in plate II and is adapted to normally hold valve Against its seat, Q8. Both plates 41 and ii and the outwardly flanged part of member 39 are provided with-openings which receive screws 83 adaptedtobe threaded into threaded openings 38 provided in the piston 28.

The heads of screws 55 tightly clamp the plates 4! and 6| and the cylindrical spider like member 39 in position in or on the piston. It will be seen that the passage through piston 28 is normally closed by two valves arranged one above the other and in series relation with the flow of fluid through the passage.

When the pistons 28 are reciprocated, during operation of compressor In by motor l8, suction created by the initial downward movement of a piston in the cylinder 29 causes the upper valve 38 to be raised from itsseat 48. This initial movement of piston 28 thereby establishes communication'between the upper portion of cylinder 29 and the chamber provided by the member 39' valve remains closed in' the manner described eliminates the objectionable popping noise which occurs or which is created in the manner hereinbefore pointed out. Further downward move- 'ment of piston 28 then. increases the suction created above the piston and in the chamber at a,

the piston below valve 38 to cause the lower piston valve 35 to open. Refrigerant gas or any other fluid may then freely pass through the valved passages provided in piston-28 into the compressor cylinder 29 above the piston. Both valves 35 and 36 will close at the bottom of the stroke of the piston 28 and the refrigerant vapor trapped in cylinder 29, between the top of piston 28 and the outlet check valve 32 will be com.-,

pressed and forced under pressure, through the outlet opening at the top of the cylinder and controlled by valve 32, into the condenser l2 through conduit II. The chamber provided in to be compressed by the piston- The eiiiciency arrangement.

From the foregoing it is apparent that l have provided an improved valve construction or arrangement for compressors which is quiet in operation and capable of operation over a long period of time. My improved double pistonvalve arrangement is' constructed so as to be of maxi- -mum'efllciency while at the same time eliminating objectionable noises inherent in the operation of ordinary compressors having but a single piston 28 by the member 39 is small and its volume does not therefore greatly reduce the volume .of fluid flowing into the cylinder 29 and adapted valve'incorporated in the piston or pistons thereof. The improved piston and double valve construction can be manufactured assembled in a compressor at low cost to ren er-the compressor capable of use in syste such as refrigerating'- systems of household refrigeratingapparatus where quiet operation of the compressor is of paramount importance.

While the form of embodiment of the invention as herein disclosed'constitutes a preferred a fluid from one side of the piston into the cylinder on the opposite side thereof, a disc valve for controlling the passage of fluid through said piston, spring means for normally maintaining said valve in closed position, a second disc valve for also controlling the passage of fluid through said piston, said valves being carried by said piston in series relation one above the other, spring means separate from said first named spring means for normally maintaining said second valve in closed position, said spring means for one of said valves being constructed and arranged to cause said one valve to move into open position in response to suction pressure created on one side thereof by a predetermined initial movement of said piston within the cylinder, and said spring means for the other oi said valves being'constructed and arranged to cause said other valve to remain closed during movement of said one valve to open position and to cause movement of said other valve into open position in response to suction pressure created on the one side thereof after opening of said one valve upon movement of the piston beyond, said predetermined initial movement thereof.

WILLIAM w. WATT: v 

